Top vacuum corrugation feeder with a valveless feedhead

Abstract

A top vacuum corrugation feeder is disclosed that employs a vacuum feedhead working in conjunction with an air knife to feed sheets from the top of a stack. The feedhead is valveless and has a vacuum applied thereto during the entire feed cycle in order to increase reliability and decrease minimum feed speed.

What is claimed is: 
     
       1. A high speed top sheet separator-feeder for separating and forwarding sheets including flimsy sheets seriatim from the top of a stack of sheets, comprising a stack tray for supporting a stack of sheets to be fed, endless vacuum belt means extending through at least the front end of the sheet stack tray for acquiring and advancing the top sheet of the stack, said vacuum belt means extending across a support surface having vacuum ports therein for positioning a negative pressure at the back of the belt means, and wherein the motion of said vacuum belt means is adapted to cease prior to the trail edge of the acquired sheet exposing all of said vacuum ports, air knife means positioned in front of the stack tray for applying air pressure to the sheets in the stack tray to separate the top sheet from the next adjacent sheet, and vacuum means for applying a continuous and uniform negative pressure to said vacuum ports during the feeding of sheets from the stack tray in order to increase the through put of said separator-feeder by acquiring the next sheet to be fed simultaneously with said cease of motion of said vacuum belt means such that said next sheet assumes a concaved appearance. 
     
     
       2. A high speed top sheet separator-feeder apparatus for separating and forwarding substrates including flimsy substrates in seriatim, comprising: support means for supporting a stack of substrates, said support means having front, rear and side walls attached thereto, said rear and side walls overlapping the top of the stack;   air knife means located at the front of the substrate stack and adapted to apply air pressure to the stack in order to separate the top substrate of the stack from the next adjacent substrate;   vacuum means in position above the front edge of the stack for applying a vacuum with force sufficient to acquire the top substrate from the stack;   corrugation means for corrugating substrates as they are fed from the stack;   belt means entrained over said vacuum means and adapted to forward said substrates after they have been acquired by said vacuum means and wherein the forwarding of the substrates by said belt means ceases prior to the trail edge of an acquired substrate leaving said vacuum means; and   means for continuously running said vacuum means with a constant and uniform negative pressure during an entire feeding of substrates from said support means such that the next substrate to be fed after the acquired substrate is captured while the forwarding of the acquired substrate has ceased.   
     
     
       3. A high speed top sheet separator-feeder for separating and forwarding sheets including flimsy sheets seriatim from the top of a stack of sheets, comprising a stack tray for supporting a stack of sheets to be fed, endless vacuum belt means extending through at least the front end of the sheet stack tray for acquiring and advancing the top sheet of the stack, said vacuum belt means extending across a support surface having vacuum ports therein for positioning a negative pressure at the back of the belt means, air knife means positioned in front of the stack tray for applying air pressure to the sheets in the stack tray to separate the top sheet from the next adjacent sheet, and vacuum means for applying a continuous and uniform negative pressure to said vacuum ports during the feeding of sheets from the stack tray in order to increase the through put of said feeder and wherein said vacuum belt means is stopped prior to the trail edge of the acquired sheet exposing all of the vacuum ports in said support surface in order to prevent multifeeding by allowing all sheets other than the next sheet to be fed to fall back on top of the stack. 
     
     
       4. The high speed feeder of claim 3, wherein the next sheet after the top sheet in said stack to be acquired by said vacuum belt means is first captured at a position between front and rear edges of said next sheet while the front and rear edges of said next sheet rest against the remaining sheets in the stack. 
     
     
       5. The high speed feeder of claim 4, wherein the center portion of said next sheet to be fed is the first area of said next sheet to be acquired by said vacuum belt means creating a concaved appearance in said next sheet before the top sheet has been fed completely from the stack tray. 
     
     
       6. The high speed feeder of claim 3, wherein the next sheet after the top sheet in said stack to be fed is acquired by said vacuum belt means as soon as the previously acquired sheet partially exposes said vacuum ports in said support surface. 
     
     
       7. The high speed feeder of claim 3, wherein the next sheet to be fed is acquired while simultaneously feeding the sheet previously acquired by said vacuum belt means. 
     
     
       8. A top sheet separator-feeder apparatus for separating and forwarding substrates including flimsy substrates in seriatim, comprising: support means for supporting a stack of substrates, said support means having front, rear and side walls attached thereto, said rear and side walls overlapping the top of the stack;   air knife means located at the front of the substrate stack and adapted to apply air pressure to the stack in order to separate the top substrate of the stack from the next adjacent substrate;   vacuum means in position above the front edge of the stack for applying a vacuum with force sufficient to acquire the top substrate from the stack;   corrugation means for corrugating substrates as they are fed from the stack;   belt means entrained over said vacuum means and adapted to forward said substrates after they have been acquired by said vacuum means and;   means for continuously running said vacuum means with a constant and uniform negative pressure during an entire feeding of substrates from said support means such that after the top substrate in said stack has been acquired by said vacuum means the center portion of the next substrate to be fed is also acquired by said vacuum means while the front and rear portions of said next substrate to be fed rest upon the substrate stack until feeding of said top substrate has been accomplished.